condition mean min max ZT0-3 3.857495 3.62584 4.08915 ZT4-7 5.08277 5.08277 5.08277 ZT8-11 4.7334499999999995 4.7334499999999995 4.7334499999999995 ZT12-15 0 0 0 ZT16-19 7.892250000000001 7.892250000000001 7.892250000000001 ZT20-23 6.597645 6.597645 6.597645